Coronary artery disease is a common ailment that affects millions of people. Coronary artery disease may cause the blood vessels providing blood to the heart to develop lesions, such as a stenosis (abnormal narrowing of a blood vessel). As a result, blood flow to the heart may be restricted. A patient suffering from coronary artery disease may experience chest pain, referred to as chronic stable angina during physical exertion or unstable angina when the patient is at rest. A more severe manifestation of disease may lead to myocardial infarction, or heart attack. Significant strides have been made in the treatment of coronary artery disease including both medical therapy (e.g. statins) or surgical alternatives (e.g., percutaneous coronary intervention (PCI) and coronary artery bypass graft surgery (CABG)). Invasive assessments are commonly used to assess the type of treatment a patient may receive. However, indirect or noninvasive assessments for formulating a patient treatment are being explored and developed.
One way of assessing the need for treatment, is observing blood supply to tissue, since cardiovascular disease reduces blood supply to tissue (e.g., myocardial tissue). Several diagnostic modalities (e.g., computed tomography (CT angiography) and magnetic resonance imaging (MR angiography)) provide an assessment of blood supply to tissue (e.g., perfusion, viability, or biomedical aspects of the tissue). While blood supply may provide some input for evaluating medical treatment, assessment of blood supply alone is inadequate for determining a targeted treatment. Heart disease is contingent on several more factors.
The inadequacy is made apparent by the fact that medical treatments prescribed are often more extreme than necessary. For example, PCI and bypass grafts are highly overused. In addition, PCI and bypass grafts are sometimes not used effectively, for instance, due to incorrect placement or placement at stenoses that are not functionally significant. Thus, at a threshold level, a need exists to accurately assess the severity of cardiovascular disease in determining which treatment to apply to a patient. Furthermore, for PCI and bypass grafts, an accurate assessment of locations for applying treatment is important. Thus, a desire exists for improving treatment by targeting treatment sites, both by accurately determining the severity of a disease and by pinpointing locations effective in treating the disease.
The foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.